作 者 ：傅丰贝,陆文娟,李伏生
期 刊 ：植物营养与肥料学报 2014年 20卷 6期 页码：1378-1386
关键词：根区局部灌溉；轻度亏水；有机无机氮比例；玉米；生理特性；水分利用效率；
Keywords:partial root-zone irrigation, mild water deficit, ratio of inorganic to organic N, maize, physiological index, water use efficiency,
摘 要 ：【目的】根区局部灌溉(PRI)是一种节水灌溉方法,包括分根区交替灌溉(AI)和固定部分根区灌溉或称部分根区干燥灌溉(PRD),其中PRD技术是在作物生育时期一半根区总不灌水,另一半根区充分灌水,AI技术则是在作物生育期内根据生育时期和土壤水分情况交替对根系两侧进行灌水。本文研究在不同施肥条件下,拔节前期至抽雄期不同时段采用PRI对玉米生理指标、 干物质积累和水分利用效率(WUE)的影响,以期为玉米合理灌溉和施肥提供依据。【方法】采用盆栽方法,设3种灌溉方式为常规灌溉(每次对盆内全部土壤均匀灌水)、 分根区交替灌溉(每次交替对盆内1/2区域土壤灌水)和固定部分根区灌溉(每次固定对盆内1/2区域土壤灌水);2种灌水量为正常灌水(70%~80%θf,θf为田间持水量)和轻度亏水(60%~70%θf); 2种施肥处理为100%化肥氮、 80%化肥氮+20%有机氮。在拔节期至抽雄期进行12 d、 24 d和36 d根区局部控水灌溉处理。分别测定玉米的光合速率、 气孔导度、 叶绿素、 类胡萝卜素、 可溶性糖和脯氨酸含量,总干物质量、 耗水量和水分利用效率。【结果】不同灌溉方式、 灌水水平和有机无机氮比例处理对拔节中期、 拔节末期和抽雄期玉米光合速率、 气孔导度、 类胡萝卜素含量、 叶绿素含量和可溶性糖含量的影响不显著,灌水量对抽雄期脯氨酸含量的影响也不显著,表明控水持续时间长短,根区局部灌溉、 轻度亏水和有机无机氮配施不会显著影响玉米生理指标。与常规灌溉相比,拔节前期至抽雄期3个控水时段根区局部灌溉对玉米总干物质量和水分利用效率的影响虽不显著,但是显著降低了玉米耗水量,在正常灌水量和单施化肥氮条件下,拔节末期控水24 d和抽雄期控水36 d,根区局部灌溉可分别提高水分利用率24.4%和16.3%。此外,轻度亏水、 有机无机氮肥配施(80%化肥氮+20%有机氮)对玉米生理指标、 总干物质量和水分利用率的影响也不显著。【结论】在正常灌水量和单施化肥氮条件下,在拔节期至抽雄期进行根区局部灌溉可显著降低玉米耗水量,而对玉米生理指标和总干物质量无明显影响,因而显著提高玉米水分利用效率。
Abstract:【Objectives】Partial root-zone irrigation (PRI) is a water-saving irrigation method, including alternate PRI (AI) and fixed PRI (FI) or partial root-zone drying irrigation (PRD). With PRD, half of root-zone is fully irrigated while the other not irrigated during the growth stage of crop. With AI, the both sides of root-zone are alternatively irrigated depending on the growth stage and soil water condition. The effects of PRI at different water-control durations during the early jointing to tasseling stages on the physiological indices, dry matter accumulation and water use efficiency (WUE) of maize were investigated under different fertilization conditions, so as to provide scientific basis for rational irrigation and fertilization of maize. 【Methods】 A pot experiment was conducted. Three irrigation methods with two irrigation levels each and two fertilization treatments were designed. The three irrigation methods include: conventional irrigation (soil was evenly watered), alternate PRI (the two halves of a pot soil were alternately watered) and fixed PRI (only half of the soil in the pot was watered); two irrigation levels include: conventional irrigation (70%-80%θf, θf is field capacity) and mild water deficit (60%-70%θf); two fertilization treatments were 100% chemical N and 80% chemical N + 20% organic N. The three water-control durations were 12, 24 and 36 days from the jointing stage to tasseling stage. The leaf photosynthetic rate, stomatal conductance, the contents of chlorophyll, carotenoid, soluble sugar and proline, total dry mass, water consumption and WUE of maize were measured. 【Results】 Different irrigation methods, irrigation levels and ratios of inorganic to organic N do not significantly affect leaf photosynthetic rate, stomatal conductance, contents of chlorophyll, carotenoid and soluble sugar of maize at the early and middle jointing stages and tasseling stage, and irrigation level does not significantly affect proline content of maize at the tasseling stage either, indicating that PRI, mild water deficit and combined application of inorganic and organic N do not significantly affect physiological indices. Compared to conventional irrigation, PRI at different water-control duration does not significantly affect total dry mass and WUE, but significantly reduces water consumption at the early jointing to tasseling stages in most cases. However, under normal irrigation (70%-80%θf) and only chemical N treatment, PRI increases the WUE by 24.4% and 16.3% at 24 d (later jointing stage) and 36 d (tasseling stage) after water control, respectively. Moreover, mild water deficit (60%-70%θf) and combined application of inorganic and organic N (80% chemical N + 20% organic N) do not significantly affect physiological indices, total dry mass and WUE. 【Conclusions】 Partial root-zone irrigation at the jointing to tasseling stages significantly reduces water consumption, while it has limited effect on physiological indices and total dry mass, thus it enhanced water use efficiency significantly under normal irrigation with only chemical N.
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